The majority of supersonic turbojet engines used in military applications are equipped with a post-combustion device. This device appears in the form of a channel situated between the turbine and the nozzle, wherein injection ramps provide a fuel supplement able to complete the combustion of unburnt hydrocarbides in the combustion chamber and thus raise the temperature of the ejection gases. The contribution of fuels is considerable and high temperatures of about 2100.degree. K. are attained (mean ejection temperature). These temperatures may locally reach 2300.degree. K.
For turbojet engines equipped with axisymmetrical nozzles, the channel has a cylindrical shape. As shown on FIG. 1, this channel 6 is connected at its upstream end to the downstream flange of the exhaust housing 4 placed downstream of the combustion chamber 3 and at its downstream end directly at the upstream ferrule 5 of the nozzle 2.
Having regard for the temperatures existing in this type of channel, it is essential to provide a thermal protection jacket. This jacket is kept spaced from the internal wall of the channel and coaxial with the latter by sliding fasteners. A flow of cooling air, which may be the secondary air in the case of a twin-flow turbojet engine, circulates between the internal portion of the channel 6 and the outer wall of the jacket 1.
French patent FR-A-2 646 880 describes a thermal protection jacket formed of a set of tiles overlapping laterally and longitudinally. The rows of successive tiles are offset by a tile half width. The fixing of the upstream tiles is effected by downstream straps traversing windows upstream of the downstream tiles and by clamps. The tiles may be made of metallic, ceramic or composite materials. There is extremely high pressure outside the jacket with respect to the pressure existing inside. The jacket is therefore subjected to both thermal and mechanical stresses. Thus, it undergoes a sort of compression tending towards an implosion phenomenon. The sectors of the jacket need to withstand these significant tangential stresses. For sectors or tiles made of a composite material, it is difficult to have the tangential forces borne by the ends of the tiles due to the pressure difference existing on both sides of the jacket. Accordingly, the forces are taken up by the linking elements.
The aim of the invention is to provide a sectorized tubular structure made of a composite material and working on an implosion principle, while being able to resist tangential stresses at the links between the various sectors of the structure and the linking elements.